1. Field of the Invention
The present invention relates to a belt type continuously variable transmission in which oil is supplied to a pulley oil chamber, a canceler oil chamber and an endless belt through an oil passage formed in a shaft supporting the pulleys.
2. Description of the Prior Art
A belt type continuously variable transmission such as disclosed in Japanese Patent Application Laid-open No. 7-174193 is known, in which an endless belt is passed or reeved around a drive pulley on an input shaft and a driven pulley on an output shaft. The speed change ratio or gear shift ratio is changed by increasing the groove width of one of the drive and driven pulleys and reducing the groove width of the other.
In such a belt type continuously variable transmission, an oil path is provided to supply oil to the pulley oil chamber to change the groove width of the pulley, another oil path is provided to supply oil to the canceler oil chamber to cancel the centrifugal oil pressure produced in the pulley oil chamber, and a further oil path is provided to supply oil for lubricating the endless belt. The oil paths are formed as separate hydraulic systems in the input shaft and the output shaft. Having multiple oil paths simultaneously in the shafts gives rise to a problem of requiring a large-capacity oil pump to deliver an increased amount of oil required.